Many electronic devices or systems, such as computers, tablets, and cellular phones, include receivers to receive signals. The signals carry information (e.g., data) transmitted from one device to another device. Some conventional receivers use current-mode-logic (CML)-type comparator circuits to receive input data signals. Some other conventional receivers use complementary metal-oxide semiconductor (CMOS)-type comparator circuits to receive input data signals. CML comparator circuits can operate at a relatively higher speed, but they usually consume a relatively higher amount of power. CMOS comparator circuits normally consume a relatively lower power, but they are typically slower than CML comparator circuits, especially when the input data signal is small. Thus, each type (CML-type or CMOS-type) of comparator circuit has its own drawbacks.